1. Field of Invention
The field of the invention relates to evaluation of the orientation and dimension of an elementary object having a substantially cylindrical revolution shape as well as the three-dimensional reconstruction of an object formed from a series of these elementary objects or assimilable by approximation to a series of these elementary objects, all from a projection bidimensional image in a radiography device.
2. Description of the Prior Art
In some interventional X-ray procedures, the practitioner is encouraged to insert catheters and others guide-wires inside the body of the patient being treated. Catheters can serve for injecting a contrast liquid, such as iodine, and the guide-wires can be utilised for placing therapeutic instruments such as balloons, vascular endoprostheses, etc. The commonality of these catheters and guide-wires is that they are curvilinear structures with a substantially circular cross-section.
Within the scope of these interventional procedures, and particularly in neurosurgery, the vascular network of the patient being treated is very complicated and a bidimensional projection very often provides insufficient information. Because of this, it is necessary to construct three-dimensional models of this vascular network and provide an aid for localisation of instruments in these three-dimensional models. This need emerges also in interventional cardiology where the role of three-dimensional models is growing with support from the development of cardiac scanners.
In this context, it is admitted that a single bidimensional view of the interventional instrument is not sufficient to construct a three-dimensional representation thereof. Some techniques have been developed from biplanar acquisitions which simultaneously utilise two bidimensional projections at different angles. However, such projections are not sufficient for reconstructing a curvilinear structure in three dimensions without any ambiguity, such as a guide-wire or a catheter. Also, this needs a dose of radiation greater than for acquisition of a single image, which is never preferable. Such techniques are described in articles by Merle, A. B. et al., titled “3D-reconstruction of the deformable coronary tree skeleton from two X-ray angiographic views” in “Computers in Cardiology”, of Sep. 13-16, 1998, pages 757-760, and by Baert. S. A. M. et al. titled “Three-dimensional guide-wire reconstruction from biplane image sequences for integrated display in 3-D vasculature”, in Medical Imaging, IEEE Transactions, Volume 22, Issue 10, October 2003, pages 1252-1258. In the scope of interventional cardiology, three-dimensional reconstruction using traditional methods seeking to acquire images at different angulations is generally limited by the movement between the images induced by cardiac and respiratory movement of the patient.